Letter-scale



T. FAIRBANKS.

Balance Scales.

Patented Nov. 8, 1859.

UNITED STATES PATENT QFFICE.

THADDEUS FAIRBANKS, OF ST. JOIINSBURY, VERMONT.

LETTER-SCALE.

Specification of Letters Patent No. 26,026, dated November 8, 1859.

T 0 all whom it may concern:

Be it known that I, THADDEUS FAIRBANKS, of St. J ohnsbur in the countyof Caledonia and State of ermont, have invented an Improved Scale for lVeighing Letters, &c.; and I do hereby declare that the same is fullydescribed and represented in the following specification and theaccompanying drawings, of 'which Figure 1, denotes a side elevation ofsuch scale, Fig. 2, a top view, Fig. 3, a longitudinal and verticalsection, and Fig. t, a transverse section, taken through the plate, itsframe and pendulous weight.

In the drawings, A, represents the foundation or base for supporting theoperative parts. From the said base part, two vertical standards, orcolumns, B, C, extend upward and have mortises, a, Z), made respectivelyin their top parts, the same being for the reception of a wedge or knifeshaped bar, D, whose ends, 0, (Z, rest respectively in the saidmortises. The said bar, D, passes transversely through the graduatedarm, E, and serves as a fulcrum for it, such arm being provided withdivisions, to mark either the whole ounces, or fractions of the same, asshown in the drawings.

At or near the rear part of the arm, E, and over the same, as shown inthe drawings, a plate, F, is suspended, such plate having a rectangularframe, H, attached to its under side, as shown in Fig. 4t. From theinner vertical sides of said frame, ears, or projections, h, z', extend,such being respectively recessed on their under sides for the receptionof the ends of a knife edged bar, I, which extends transversely throughthe graduated arm, and near to its rear end, as shown in Fig. t. Bymeans of the said projections and bar, the plate is sustained andrendered capable of being easily vibrated. To the middle of the lowerpart of the said rectangular frame a rod, I, is attached, which extendsdownward through a hollow column, L, (which projects upward from thebase or foundation, as shown in the drawings,) and has a weight, K,screwed or firmly aflixed to its lower end, such being for the purposeof preserving the plate E, in a horizontal position, whatever may be theinclination of the said graduated arm. From the rear part of the saidhollow column, a standard, M, extends upward, its

top surface serving as a bearing for the rear extremity of the graduatedarm, to rest upon when the upper and lower faces of the said graduatedarm are in horizontal planes-a loop or eye, g, passing around the rearextremity of the arm serving to prevent it from receiving too great aninclination, or such as would cause the poise, N, by its gravity, toslide on the arm.

A machine constructed in the above described improved manner is veryconvenient and useful for merchants and others; it being not only verysimple in construction, but very effective in operation.

I do not claim balancing a scale pan and weighing lever by means of apendulous weight applied to a straight arm extending downward from thecentral part of the pan; nor do I claim supporting a scale pan on theprongs of a bifurcated steelyard, extending a rod or arm downward fromthe middle of the pan and jointing such rod at its lower end to an armparallel to the steelyard and hung at its other end on a fulcrumsituated immediately under that of the steelyard; nor do I claim underthis latter construction the application of a stop in front of and tothe forked steelyard so as to act in concert with a stationary staple orits equivalent.

In my construction of scale, I make the weighing lever or steelyardwithout any bifurcation or fork, but simply as a straight bar providedwith knife edges for supporting the bearing of a pendulous weight, andsuch weight I hang upon such knife edges, by means of a forked rodfurnished with bearings to receive such knife edges. Furthermore Iextend the front end of the weighin or steelyard lever into a stationary staple, (1., arranged at the top of the post, N, as shown in thedrawings, such staple being made so as to allow the said front end toplay freely up and down a short distance.

By my construction I not only attain the advantages of the pendulousweight over the forked lever, but I employ the weight of the fork of theforked arm to aid in or facilitate the maintenance of the horizontalityof the scale pan. I also avoid the expense of connecting the stoppingprojecof a bar, I, xtended from the steelyard as 10 specified, but Witha bar steelyard, E, made Without any fork and extended into a stationarystaple or stop, g, the Whole being ar- 5 My improved manufacture ofletter scale, ranged in manner and to operate as specified. as made notonly With its pendulous Weight THADDEUS FAIRBANKS.

K, connected with the scale pan, F, by a Witnesses: forked arm H, H, I,provided with bearings THOMAS SPOONER, h, '5, for receiving and restingon knife edges HORACE FAIRBANKS.

tioii of the steelyard to the steely'ai'd loar or its prongs by a forkor curved bar of connection.

Consequently What I claim is-

